Stair climbing exercise apparatus



FIG. 1 is a front perspective view of a stair climbing exercise apparatus showing our design;

FIG. 2 is a side elevational view thereof, the side opposite being substantially a mirror image;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof; and

FIG. 6 is a bottom view thereof. 

The ornamental design for a stair climbing exercise apparatus, as shown and described. 